The invention concerns a work device with a guide bar on which a chain is driven in circulation, wherein the work device comprises a tensioning device for the chain, wherein the tensioning device comprises a tensioning member that is acting on the guide bar in direction of a longitudinal center axis of the guide bar, and wherein the tensioning device comprises a rotatably supported adjusting member that is connected by a threaded connection with the tensioning member, wherein turning of the adjusting member about its axis of rotation effects a movement of the tensioning member in the direction of the longitudinal center axis of the guide bar, wherein the adjusting member comprises on its outer circumference a threaded section with at least one thread turn that is provided for engagement with at least one threaded section of the tensioning member, and wherein the adjusting member comprises an actuating contour that comprises at least one recess for turning of the adjusting member by an operator.
WO 2005/108030 A1 discloses a power saw with a saw chain that is driven to circulate about guide bar and can be tensioned by means of a tensioning device. The tensioning device comprises a rotatably supported adjusting screw with a screw head and a screw shaft. The screw shaft acts by means of a threaded connection on a tensioning member secured on the guide bar. Turning of the adjusting screw effects by means of the threaded connection a lengthwise displacement of the guide bar so that the saw chain is tensioned. In order for the saw chain to be tensioned, the operator must apply a great torque to the screw head. Due to the small diameter of the screw shaft, the transmittable tensioning forces are limited.
The invention has the object to provide a work device of the aforementioned kind that has a simple configuration and enables transmission of comparatively high tensioning forces.